That file is around 50mb with a couple of 2k images + some drop shadows. I'm using a 2016 MBP with touch bar, 16gb Ram, Radeon 455 and a 4k external Samsung display.

Can someone please try and create a new file, draw a simple rectangle and move it around for like 20 sec and see how much CPU Sketch is using? For me, it goes up to 175-200%.

Did the exact same thing in photoshop and it never went past 45%, Figma (in Safari) was around 80%. I find it ridiculous that 1 Rectangle and 1 artboard would use 200%.

Did a clean install, disabled all plugins, contacted support and I still can't find a solution.

Any suggestions are appreciated!

PS: read in a post that Sketch is using some "Core Rendering" thing that pretty much is 100% CPU and doesn't use the GPU at all. If that's the case, that would explain why it's struggling when the CPU needs to drive the Retina display + 4k external one. Anyone got more info on this?